M4.7 Earthquake 191 km WSW of Riverton, New Zealand — October 19, 2021
2021-10-19 21:11:20 UTC (2021-10-19) · approx. 8:11 AM UTC+11 local
On October 19, 2021 at 21:11 UTC, a magnitude 4.7 shallow crustal earthquake struck 191 km WSW of Riverton, New Zealand, at a depth of 18.3 km and coordinates -46.8218°, 165.6090°.
Physical scale: An earthquake of magnitude 4.7 releases seismic energy equivalent to roughly 169 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.1 km — a useful intuition for the size of the slip patch on the fault.
The epicenter is located in New Zealand, a region characterized by the Hikurangi subduction zone in the North Island and the Alpine Fault in the South Island. The nearest mapped fault system is the Alpine Fault. View all earthquakes in New Zealand.
Learn more: Magnitude scale · Aftershock sequences
Earthquake Details
165.6090°E
Technical Information
Common Questions
How strong was the magnitude 4.7 earthquake near Riverton, New Zealand?
The magnitude 4.7 earthquake that struck 191 km WSW of Riverton, New Zealand on October 19, 2021 at 21:11 UTC had a depth of 18.3 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at -46.8218°, 165.6090°, which is 191 km WSW of Riverton, New Zealand. View all earthquakes in New Zealand.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.7 earthquakes can continue for several days and gradually diminish over time.
Has New Zealand had earthquakes this big before?
The largest recorded earthquake in New Zealand was the M8.2 Wairarapa earthquake of January 23, 1855. Today's magnitude 4.7 event is significantly smaller than that historical record.
Authoritative source: USGS event page (event ID: us6000fvzd). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, October 19, 2021). M4.7 Earthquake 191 km WSW of Riverton, New Zealand — October 19, 2021. Retrieved December 25, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000fvzd/